The WO 2006/134546 A2, WO2006/079998 and Bruls et al. (“Rapid integrated biosensor for multiplexed immunoassays based on actuated magnetic nanoparticles”, Lab Chip, 2009, 9, 3504-3510—Oct. 13, 2009) disclose magnetic biosensors with a sensing surface that is coated with binding sites which can specifically bind to target components either carried by magnetic beads or labeled by magnetic beads. Documents further disclose various procedures to dynamically distinguish between magnetic beads which are specifically or un-specifically bound to the binding sites, respectively.